Ch. 20- 24 Physics Questions Flashcards
While using a linear sequential array transducer during a color Doppler exam, the shape of the gray scale image is most often ________, whereas the shape of the color Doppler portion of the image is _____.
rectangular, parallelogram
Rectangular, sector
sector, trapezoid
Square, rectangular
Rectangular, parallelogram
What is the meaning of the term “analysis” in the context of spectral analysis of Doppler signals?
Building a sophisticated signal from components
Building a simplified signal from components
identifying the building blocks or components of complex signal
Measuring a complex signal, then modifying its information content
identifying the building blocks or components of complex signal
the analysis of Doppler spectra using ___________ is most accurate.
Zero- crossing detectors’
Fast Fourier Transforms
Time interval histograms
Chirp-Z transforms
Fast Fourier Transforms
Spectral analysis of color flow Doppler is most commonly performed by which of the following techniques?
Zero- crossing detectors’
Fast Fourier Transforms
autocorrelation
Chirp-Z transforms
Autocorrelation
Acoustic artifacts include what?
images of reflectors in an inappropriate position
images of reflectors with improper shape
images of reflectors with incorrect brightness
images that do not correspond to anatomical structures
all the above:
images of reflectors in an inappropriate position
images of reflectors with improper shape
images of reflectors with incorrect brightness
images that do not correspond to anatomical structures
Which of the following is not a potential cause of artifact in diagnostic imaging?
Operator error
equipment malfunction
patient motion
ultrasound physics
none of the above
none of the above
Ultrasound systems are designed to automatically __________.
Display similar structures with equal brightness, regardless of depth
position structures at the correct depth, regardless of the medium
display all reflections on a line corresponding to the main axis of the sound beam, regardless of refraction
select the optimal beam width based on the clinical application
display all reflections on a line corresponding to the main axis of the sound beam, regardless
Six distinct, equally spaced reflections appear on an image at ever increasing depths. what type of artifact is this?
Reverberation
ring down
mirror imaging
longitudinal resolution
reverberations
Which situation will commonly produce reverberation artifact?
two masses that lie, perpendicular to the sound beam’s main axis
two week reflectors that lie close to each other along the axis of the beam
two strong reflectors that lie along the main axis of the beam
a single highly reflective mass
two strong reflectors that lie along the main axis of the beam
What are the characteristics of a medium that produces comet tail artifact?
weak reflectors, closely spaced, low propagation speeds
strong reflectors, widely spaced, high propagation speeds
strong reflectors, closely spaced, low propagation speed
strong reflectors, closely spaced, high propagation speed
strong reflectors, closely spaced, high propagation speed
What is the most likely cause of ring down artifact?
refraction
inversion
reabsorption
reflection
reflection
Where are shadowing artifacts commonly seen on an acoustic scan?
Deeper than a structure with a high impedance
Shallower than a structure with a low propagation speed
deeper than a structure with a high attenuation
Alongside of a structure with a low elastance
deeper than a structure with a high attenuation
How is shadowing artifact expressed?
Positioning structures too deep on the image
locating structures in improper lateral position
placing reflections in multiple locations
reflectors being absent on the image
reflectors being absent on the image
which of these produces shadowing?
reverberation
multipath
reflection
attenuation
attenuation
